MINNEAPOLIS — An instructor at the flight school Zacarias Moussaoui attended before the Sept. 11 attacks is $5 million richer for his efforts to alert authorities — but colleagues say he wasn't the only one sounding an alarm.

Clarence Prevost, 69, got the payout Thursday as part of the State Department's "Rewards for Justice" program, which mainly seeks information about perpetrators or planners of terrorist acts against U.S. interests and citizens abroad.

The ceremony was closed and the State Department wouldn't identify the recipient, in keeping with the policy of the program. But two Bush administration officials, speaking on condition of anonymity because they weren't authorized to talk publicly about the matter, said the reward went to Prevost.

Prevost, a former Navy pilot who goes by the nickname "Clancy," became a key witness at Moussaoui's trial and eventual conviction as a Sept. 11 conspirator, testifying that he urged his bosses at the Pan Am International Flight Academy outside Minneapolis to call the FBI in August 2001 because he was suspicious of Moussaoui, an inexperienced pilot seeking commercial jetliner training.

Prevost said during the trial that he urged flight school officials to call the FBI and one day an agent showed up to ask him questions about Moussaoui.

News of the reward came as a surprise to two other Pan Am flight instructors, Tim Nelson and Hugh Sims, who also have been credited with tipping the FBI to Moussaoui and were honored by the Senate in 2005 with a resolution that commended their "bravery" and "heroism."

Nelson, 47, of St. Paul, Minn., said he planned to contact Minnesota's senators to ask for an explanation of the reward.

"It was never done for the reward, but when you give $5 million to a person who didn't call the FBI and didn't put his job on the line, are they rewarding someone for calling the FBI or for testifying? And the only reason he was testifying was because he was the instructor," Nelson said of Prevost.

Sims, in a phone interview from Fort Myers, Fla., said he didn't want to comment "till we get a few things straightened out." Sims recounted meeting Moussaoui at Pan Am on a Monday, and said that two days later he and Nelson each called the FBI separately.

"He was certainly there but he didn't call the FBI. I have no idea why he received the reward," Sims said.

Phone calls to a listing for Prevost in Coral Gables, Fla., an upscale Miami suburb, were not answered today.

After his arrest, Moussaoui sat in jail for 3 1/2 weeks on an immigration violation, saying little to investigators before hijacked planes slammed into the World Trade Center and the Pentagon or crashed in a Pennsylvania field on Sept. 11.

The Minneapolis FBI agents who responded to the tips were unable to persuade their superiors in Washington to seek a national security warrant to search Moussaoui's belongings and laptop computer.

Moussaoui later confessed to being the "20th hijacker" and was sentenced to life in prison without parole in 2006 after a trial marked by numerous outbursts, conflicts with his lawyers and questions about his status, if any, within Osama bin Laden's al-Qaida network.

He told jurors he was to have piloted a fifth plane on Sept. 11 and fly it into the White House.

But after the jury decided against sentencing him to death, Moussaoui recanted his testimony and denied any role in 9/11, saying he lied on the stand because he assumed he had no chance of getting a fair trial.

Rewards for Justice, which was created in 1984, has paid about $77 million in rewards to more than 50 people. The State Department says its policy is to withhold the names of the people who receive rewards, though it sometimes announces payments in high-profile cases. The largest payment the program has made was $30 million to a person whose information led to Saddam Hussein's sons, Uday and Qusay Hussein, according to its Web site.

The award to Prevost is the first to a U.S. citizen related to the Sept. 11 attacks, the administration officials said.